Search results for "TPA"

Coupling of proton translocation through ATPase incorporated into supported lipid bilayers to an electrochemical process

1997

Abstract H+-ATPase is incorporated into solid-supported lipid bilayers separated from the gold support by a peptide spacer. The translocation of protons across the lipid film to the inner side is coupled to the discharge of protons at the gold surface. The overall process is investigated by square wave voltammetry (SWV) and double potential-pulse chronoamperometry (CA). As a result, the formation of a proton gradient is monitored by SWV whereas currents measured by CA monitor the stationary state when the enzyme activity is directly coupled to the charge transfer at the electrode. These currents markedly depend on the number of ATPases present in the bilayer.

Screening for Solute Transporters in Plant Photosynthetic Membranes

2008

As compared to chloroplast envelope transporters, the field of thylakoid transporters is largely unexplored. There is evidence for several transport activities in the plant thylakoid membrane, but only a copper P-type ATPase and an ATP/ADP carrier have been so far identified at the gene level in Arabidopsis thaliana. Using in silico analyses, we have predicted the existence of approximately 15 thylakoid transporters, including phosphate transporters and cation channels. For experimental validation, we have used peptide- specific antibodies and functional analyses in heterologous system. These novel data are highly relevant to understand the transport network of the thylakoid membrane and it…

S1/2 Mechanistic insights of F1-ATPase rotation from single-molecule measurements of the power stroke

2008

Potential ATPase mimics by polyammonium macrocycles: Criteria for catalytic activity

1992

Abstract A series of polyammonium macrocycles, ranging in size from the 18-membered ring [18]aneN6 to the 36-membered [36]aneN12 were examined as potential ATPase mimics. The rates of hydrolysis of ATP were followed at pH 3.0 and 7.0 using 31P NMR and HPLC techniques. Stability constants as a function of degree of protonation, distribution curves for the ligands as a function of pH, and distribution curves for the mixed species of nucleotides, inorganic phosphate, and macrocycle were also determined. All of the macrocycles catalyzed the hydrolysis of ATP to some extent compared to noncatalyzed hydrolysis. A critical dependence on macrocyclic ring size was observed, with [21]aneN7 being the …

GTPases of the Rho Subfamily Are Required for Brucella abortus Internalization in Nonprofessional Phagocytes

2001

Members of the genus Brucella are intracellular -Proteobacteria responsible for brucellosis, a chronic disease of humans and animals. Little is known about Brucella virulence mechanisms, but the abilities of these bacteria to invade and to survive within cells are decisive factors for causing disease. Transmission electron and fluorescence microscopy of infected nonprofessional phagocytic HeLa cells revealed minor membrane changes accompanied by discrete recruitment of F-actin at the site of Brucella abortus entry. Cell uptake of B. abortus was negatively affected to various degrees by actin, actin-myosin, and microtubule chemical inhibitors. Modulators of MAPKs and protein-tyrosine kinases…

Solubilization of an oligomycin-sensitive ATPase complex fromRhodospirillum rubrumchromatophores and its inhibition by various antibiotics

1978

[Loyauté des transactions sur un marché relatif aux attributs de croyance : une analyse appliquée aux produits agro-alimentaires]

2001

International audience; Après avoir décliné la typologie des caractéristiques des produits en termes d'attributs de recherche, d'expérience et de croyance, les auteurs soulignent les mécanismes susceptibles d'assurer l'efficacité des transactions marchandes. Afin de cerner les enjeux liés à la loyauté des transactions dans le cas des attributs de croyance, ils montrent à l'aide d'un jeu simple, le caractère crucial des phases de définition, de vérification et de signalement, ces dernières nécessitant généralement l'intervention d'agents extérieurs à la transaction marchande.

Apoptosis during early development of sea urchin.

2008

Apoptosis is a genetic program of cell death that eliminates superfluous or compromised cells during development and adult life of many organisms. In sea urchin embryos, apoptosis is not only a physiological event during larval metamorphosis, but also a process induced by cadmium accumulation or other stressor like TPA (12-O-tetradecanoylphorbol-13-acetate) followed by an increase of temperature to 31°C. Apoptosis is a highly conserved process usually operated by a proteolytic cascade that involves caspase activation by two different pathways: extrinsic and intrinsic. The first one involves membrane death receptors, while the second involves mitochondria. In this work we analyzed the possib…

Evidence for essential primary amino groups in a bacterial coupling factor F1ATPase.

1980

Abstract We have found that the binding of pyridoxal-5′-phosphate to 6 primary amino groups leads to the inactivation of the enzyme. A preferential reaction of pyridoxal-5′-phosphate with the α-subunits of this enzyme can be demonstrated. The reactivity of the amino groups is influenced by various effectors. In the presence of ATP the inhibition of the ATPase activity is noncompetitive.

3'-Arylazido-beta-alanyl-2-azido ATP, a cross-linking photoaffinity label for F1ATPases.

1989

Abstract The synthesis of the 3′-arylazido-2-azido ATP derivative 3′-O-{3-[N-(4-azido-2-nitrophenyl)-amino]propionyl}2-azido-adenosine 5′-triphosphate (2,3′-DiN3ATP) is described. The bifunc­ tional photoreactive ATP analog is characterized spectroscopically. Photoaffinity labeling of F, ATPase from Micrococcus luteus by this analog results in the inactivation of the enzyme and in the formation of higher molecular weight cross-links,